Process of electric heating.



No. 757,619. PATENTED APR. 19, 1904. w. s, HORRY. PROCESS OF ELEGTRIG HEATING.

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APPLICATION FILED APR. 28. 1902.

N0 MODEL N0. 75?,619. Patented April 19, 1904.

UNITED STATES PATENT OFFICE.

WILLIAM SMITH HORRY, or NIAGARA FALLs, NEW YORK, ASSIGNOR TO UNION CARBIDE COMPANY, or NIAGARA FALLS, NEW YORK, A con- PORATION or VIRGINIA.

PROCESS OF ELECTRIC HEATING-.1

SPECIFICATION forming part of Letters Patent No. 757,619, dated Aprii 19, 1904. Application filed April 28, 1902. Serial No. 105 ,02'7. (N specimens.)

T0 all wh0m it y 001/0067: more especially a body of calcium carbid or Be it known that I, WILLIAM SMITH HORRY, of carbidforming materials, such as exists a subject of King Edward of Great Britain, rein the lower part of the furnace, (shown in siding at Niagara Falls, in the county of Ni- Figs. 1, 2) when in normal working operation.

5 agara and State of New York, have invented The furnace shown, intended forthe useof certain new and useful Improvements in Procthisprocess of heating in the production of esses of Electric Heating, of which the folcalcium carbid, comprises, an annular stack lowing is a specification. 10, of refractory-material, suchas fire-brick,

This invention relates to the art of electrichaving at its upper end a suitablemechanism I ally heating a body of conducting material, 11 for introducing raw material and preventespecially a mixture of a metallic compound ing the escape of gases, here shown as a bell and a reducing agent, and specifically a mixand hopper. Through the side of the stack ture of lime and carbon for the production of near its upper end passes a flue 12 for withcalcium carbid. The process contemplates drawing the waste gases. Near the lower por.

15 the use of a polyphase alternating current, tionof the stack are arranged one or. more preferably one of many phases, the paths of horizontal series of radial electrodes, here the several phases being so distributed within shown as cylindrical carbon rods, passing ad- .65 the conducting-body as to effect an even heatjustably through the sides of the stack. The. ing thereof. The body to be heated-is prefnumber of electrodes in each horizontal se- 2 erably circular, the active terminals of the rice is the same as the numberof separate suo source of polyphase current being placed subcessive windings in the fixed armature of the stantially in contact with the body at various dynamo. Eight electrodes,-numbered from. 7 equidistant points around its periphery and a 1 to 8, successively, are shown in each hori-, common or neutral terminal being placed in zontal series; but in practice a much larger 5 contact with someintermediate part of the number is desirable. Extendingthroughthe body, preferably its center. The source of furnace-hearth, preferably at its center, is an current preferably employed is adynamoconelectrode 9, which may be provided with a 7 5 structed to give a current of many phases central vertical tap-hole 13 to permit thewith-j with separate externalv fixed armature-winddrawal ofcalcium carbid or other molten,

3 ings, each having one end connected to a comproduct. The .carbid may flow out continumon or neutral point and the other end conously as it rises above the level of this elecnected to one of the terminals in contact with trode, or the tap-opening may be closed by a, the body to be heated. The path of the phase plug of-refractory material and openedfrom of maximum electromotive force is thus time to time for the removalof molten car- 35 caused to shift successively from terminal to. bid. Thetap-hole may, if preferred, pass di-. terminal through the body to be heated, folrectly-through the hearth. V lowing the shifting phases in the windings of Theadynamo (shown at theleft of the fur- 8 5 the dynamo. nacev in Fig. 2) comprises a fixed external ar-.

The invention will be more easily undermature having eight separate windings, numw 4 stood by reference to the accompanying drawbered l to 8, successively. One end ofeach ings, in which of these windings is connected to a common Figure l is a vertical axial section of a fur or neutral point E, and the other end of each 9 nace designed for the commercial utilization winding is connected to one of the radial elecof the process; and Fig. 2 is a horizontal sectrodes. The neutral pointE of the star-wind- 45 tion taken on line II II of Fig. 1, also showing of this dynamo is connected to the central, ing the dynamo in diagram. electrode 9 of the furnace, either directly by.

The circular body to be heated may be a a metallic conductor or through the earth. disk of metal or a metallic crucible, but is In employing this furnace to carry out the a process of .producing calcium carbid an initial charge consisting of lime and carbon is fed in through the top of the furnace. This charge may be the wellknown one containing large pieces of coke which lie in contact with each other at various points, and thereby afford direct paths for the flow of current, the lime being distributed in the interstices between pieces of coke. If the normal charge, however, consists of a non-conducting mixture of coke and lime, the furnace must be first put in operation by the use of a conducting charge or by otherwise providing initial paths for the flow of current. As soon, however, as current passes through a conducting-body in the lower part of the furnace the temperature soon rises to a point where the charge above is preheated by conduction and radiation and by the waste gases arising from the zone of reduction to a temperature which will cause it to act as a resistance-conductor before it descends into the paths of current flow. In normal working condition the body of material between the electrodes may consist of molten or partly-molten carbid or of incandescent but unreduced material, or in part of both. The process is carried out in a continuous manner by tapping out the molten carbid and supplying fresh material as required. As the current density for each electrode cannot be carried above a certain limit, the total energy which can be employed in heating the charge depends on the number of the electrodes, which may be increased as desired either by arranging a greater number in the same horizontal series or by using any desired number of superposed horizontal series. The use of a large number of electrodes is a desirable feature of this process of heating by polyphase currents, since it permits the use of relatively small electrodes without unduly heating them or their terminal connections. The use of a current of a large number of phases avoids certain difliculties incident to asinglephase current. Practically the maximum voltage of the generator is always maintained along one path through the material in the furnace, the working current thus being the maximum current of the generator instead of varying from zero to a maximum. For the same reason the total cross-section of the electrodes may be smaller than for a furnace of the same capacity using single-phase current. Any electrode may also be removed and replaced by another without noticeably interfering with the operation of the furnace. It is evident that by this process the advantages of the direct current are retained without subjecting the furnace charge to the electrolytic effect that accompanies such current. A circular furnace is preferred, since it exposes a minimum periphery for the loss of heat by radiation. The furnace may, however, be polygonal or square.

The source of current may be a transformer having a number of separate windings, one end of each winding being connected to a neutral or common point and the other being connected to one of the electrodes. The distinguishing feature of the process is the use of a source of current having a star winding and the provision of a neutral or common electrode in contact with the body to be heated.

A body of carbid-forming materials or other charge may be heated to a temperature suflicient to effect the desired reaction by employing a layer of molten iron or carbid of iron placed in the lower part of the furnace and causing the various phases of the current to pass from terminals placed around and in contact with the iron to the central electrode, the iron thereby acting as a resistance-00nductor.

No claim is made herein to the process of electrically heating a body of conducting material by causing different phases of a polyphase current to flow along paths which cross each other through said body, this invention constituting the subject-matter of my application, Serial No. 101,505, filed April 5, 1902.

I claim 1. The process of electrically heating a body of conductingmaterial, which consists in cansing difi'erent phases of a polyphase current to flow along paths which converge to a common point within said body, as set forth.

2. The process of electrically heating a body of conducting material, which consists in cansing difierent phases of a polyphase current to simultaneously flow along paths which converge to a common point within said body, as set forth.

3. The process of electrically heating a body of conducting material, which consists in causing different phases of a polyphase current to flow along paths which converge to a common point within said body, and progressively shifting the path of the phase of maximum electromotive force, as set forth.

4:. The process of electrically heating a body of conducting material, which consists in cansing different phases of a polyphase current to simultaneously flow along paths which converge to a common point within said body, and progressively shifting the path of the phase of maximum electromotive force, as set forth.

5. The process of electrically heatingabody of conducting material, which consists in placing the active terminals of a source of polyphase current substantially in contact with the body at various points, and causing different phases of the current to flow along paths which converge to a common point Within said body, as set forth.

6. The process of electrically heating a body of conducting material, which consists in placing the active terminals of a source of pol yphase current substantially in contact with the body at various points, and causing different phases of the current to simultaneously flow along paths which converge to a common point within said body, as set forth.

7. The process of electrically heating a body of conducting material, which consists in placing the active terminals of a source of polyphase current substantially in contact with the body at various points, causing different phases of the current to flow along paths which converge to a common point within said body, and progressively shifting the path of the phase of maximum electromotive force, as set forth.

8. The process of electrically heating a body of conducting material, which consists in placing the active terminals of a source of polyphase current substantially in contact with the body at various points, causing different phases of the current to simultaneously flow along paths which converge to a common point within said body, and progressively shifting the path of the phase of maximum electromotive force, as set forth.

9. The process of electricallyheating a circular body of conducting material, which consists in placing the active terminals of a source of polyphase current substantially in contact with the body at various points around its periphery, and causing different phases of the current to simultaneously flow along paths which converge to a common point Within said body, as set forth.

10. The process of electrically heating a circular body of conducting material, which consists in placing the active terminals of a source of polyphase current substantially in contact with the body at various points around its periphery, causing different'phases of the current to simultaneously flow along paths which converge to a common point within said body, and progressively shifting the path of the phase of maximum electromotive force, as set forth.

11. The process of electrically heating and reducing a body consisting of a mixture of a compound and a reducing agent, which consists in causing different phases of a polyphase current to flow along paths which converge to a common point within said body thereby heating the body to a temperature suflicient to effect reduction, as set forth.

12. The process of electrically heating and reducing a circular body consisting of a mixture of a compound and a reducing agent, which consists in using active terminals of a source of polyphase current, placed substantially in contact with the body, at various points around its periphery, and causing dif-' ferent phases of the current to simultaneously flow along paths which converge'to a common point within said body, thereby heating the body to a temperature suflicient to effect reduction, as set forth.

13. The process of producing carbids by electrically heating a body of carbid-forming materials, which consists in causing different phases of polyphase current to flow along paths which converge to a common point within said body, thereby heating the body to a temperature sufficient to effect the production of carbid, as set forth.

14. The process of producing carbids by electrically heating a body of carbid-forming materials, which consists in causing different phases of polyphase current to simultaneously flow along paths which converge to a common point within said body, thereby heating the body to a temperature sufficient to effect the production of carbid, as set forth.

15. The process of producing carbids by electrically heating a circular body of carbidforming materials, which consists in using active terminals ofa source of polyphase current, placed substantially in contact with the body of the carbid produced therefrom, at various points around its periphery, and causing different phases of the current to flow along paths which converge to a common point within said body, thereby heating the body to a temperature sufficient to efl'ect the production of carbid, as set forth.

16. The process of producing carbids by electrically heating a circular body of carbidforming materials, which consists in causing different phases of a polyphase current to flow along paths which converge-to a common point within said body, thereby heating the body to a temperature suflicient to eflect the production of carbid, and tapping off the molten carbid and feeding in fresh materials as required, as set forth.

17 The process of producing carbids by electrically heating a circular body of carbidforming materials, which consists in causing different phases of a polyphase current to simultaneously flow along paths which converge to a common point within said body, thereby heating the body to a temperature sufficient to effect the production of carbid, and tapping off the molten carbid and feeding in fresh materials as required, as set forth.

WILLIAM SMITH HORRY.

Witnesses:

E. J. PRICE, GEO. H. DANFORTI-I. 

